# Patterns of transcription factor programs and immune pathway activation define four major subtypes of SCLC with distinct therapeutic vulnerabilities

Source: https://onco.cc/key-papers/paper-gay-sclc-subtypes-inflamed-cancer-cell-2021/  
OnCo record `paper-gay-sclc-subtypes-inflamed-cancer-cell-2021` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Reanalysing gene activity in small-cell lung cancer tumours found that the fourth kind is not defined by a control protein at all but by inflammation, and it is the one kind that clearly gains from adding immunotherapy.

## Summary

Using tumour expression data and non-negative matrix factorisation, four subtypes of small-cell lung cancer were identified, defined largely by differential expression of the transcription factors ASCL1, NEUROD1 and POU2F3, or by low expression of all three signatures accompanied by an inflamed gene signature (SCLC-A, N, P and I respectively). SCLC-I experienced the greatest benefit from the addition of immunotherapy to chemotherapy, while the other subtypes each had distinct vulnerabilities, including to inhibitors of PARP, Aurora kinases or BCL-2. Cisplatin treatment of SCLC-A patient-derived xenografts induced intratumoral shifts towards SCLC-I, supporting subtype switching as a mechanism of acquired platinum resistance.

## Fields

- Kind: Key paper
- Last checked: 2026-09-25
- Journal: Cancer Cell
- Year: 2021
- DOI: 10.1016/j.ccell.2020.12.014
- Authors: Gay CM, Stewart CA, Park EM, et al.
- Findings: Four subtypes, with the fourth defined by an inflamed signature rather than by a transcription factor.; The inflamed subtype gained most from adding immunotherapy to chemotherapy.; Distinct vulnerabilities to PARP, Aurora kinase and BCL-2 inhibition across the other subtypes.; Platinum shifts tumours towards the inflamed subtype, a mechanism of acquired resistance.
- What it means: It offers the first credible explanation for why only a minority of small-cell patients get a durable benefit from checkpoint blockade, and it introduces subtype switching, which would mean retesting at relapse rather than typing once.
- Caveats: Derived from trial expression data and models rather than from a prospective biomarker-driven trial.; Subtype calls need bulk RNA, which is rarely available from a small-cell biopsy.; Switching under platinum is shown in xenografts and inferred in patients.

## Sources

- Gay et al., Cancer Cell 2021: four transcriptional subtypes of small-cell lung cancer with distinct vulnerabilities, including the inflamed subtype: https://doi.org/10.1016/j.ccell.2020.12.014
- PubMed: https://pubmed.ncbi.nlm.nih.gov/33482121/

## Connected records

- cancers: [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/), [Small-cell lung cancer](https://onco.cc/cancers/sclc/)
- technologies: [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/), [Patient-derived organoids](https://onco.cc/technologies/organoids/), [RNA sequencing & expression profiling](https://onco.cc/technologies/rna-seq/)
- targets: [ASCL1](https://onco.cc/targets/ascl1/), [AURKA](https://onco.cc/targets/aurka/), [DLL3](https://onco.cc/targets/dll3/), [YAP1](https://onco.cc/targets/yap1/)
- institutions: [MD Anderson Cancer Center](https://onco.cc/institutions/md-anderson/)
- pathways: [Lineage plasticity & neuroendocrine transformation](https://onco.cc/pathways/lineage-plasticity-neuroendocrine/), [PD-1 / PD-L1 immune checkpoint & T-cell activation](https://onco.cc/pathways/pd1-checkpoint/), [Small cell lung cancer (KEGG map)](https://onco.cc/pathways/sclc-signalling/), [The cancer-immunity cycle](https://onco.cc/pathways/cancer-immunity-cycle/), [Transcriptional machinery & addiction](https://onco.cc/pathways/transcription-addiction/)
- terms: [Drug resistance (primary and acquired)](https://onco.cc/terms/resistance/), [Hot vs cold tumours](https://onco.cc/terms/cold-vs-hot/)
- people: [John V. Heymach](https://onco.cc/people/john-heymach/)
- journals: [Cancer Cell](https://onco.cc/journals/cancer-cell/)

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